Access door



Feb. 26, 1957 J. M. Nocm ET AL AccEss DooR Filed July 15, 1955 f 4 JNVENTORS c/o/m M /Vocz' l c/ose/D/zl Perma, BY@ www ATTORNEY.

stead,A N. Y., assignorsto Republic Aviation Corporation, Farmingdale, N. Y., a corporation of Delaware Application July is, 19ss,serialv1s.368,1'6t z claims. (CL2-144129) This invention relates in general to closures and more particularly toa closure for an aperture or opening in the surface of a cooperating structure.

Among other objects the presentinvention proposes a closure or door for an access opening or aperture in a coacting structure including means for mounting the door to the structure and relative to the access opening whereby the door may be repeatedly displaced to open or close the aperture without damage to the door or to the coacting structure and which mounting means also serves to retain the door attached tothe structure when the former is displaced to its open position.

The invention also contemplates means whereby an access door or closure of the above type is secured against movement relative to the aperture in the coacting structure when the door is in the fully closed position thereof.

Moreover, the instant invention provides a door for an access opening in a cooperating structure which door is constructed and arranged to the end' that the outer surface thereof constitutes an unbroken or uninterrupted continuation of the outer surface of the structure when the door is positioned to close the" opening.

The present invention also contemplates an access door and means for mounting the ysame relative to an access opening in a cooperating structure wherein the mounting means are constructed and arranged to provide sequential, predetermined, linear and rotary displacements of the" door during the opening operation' thereof and whichv also serves upon the reversal of the sequential displacements aforesaid, to guide the door into the access opening during the closing operation thereof.

While the subject invention is primarily designed for use in aircraft structures where it constitutes a door or closure for an access opening in the skin of the aircraft or a component thereof, such as a wing, nacelle etc., it may be of general use and application. For use in conjunction with aircraft components,` it is contemplated to provide a door or closure structure capable of withstanding the Wide variations and changes inthe loads, pressures and stresses imposed on said component during flight.

With the above and other objects in view',- as will be apparent, this invention consists in the construction, combination and arrangement' of' parts all as hereafter more fully described and illustrated in the accompanying drawing wherein likerefere'nce characters designate like parts throughout the various views and wherein:

Fig. 1 is an elevation of a fragmentary structure having an access opening therein and a door or closure constructed and mounted in' accordance with the present invention for closing said opening;

Fig. 2 is a section taken along the line 2--2 of Fig. l;

Fig. 3 is a section taken alongthe line 3 3 of Fig. 1`;

Fig. 4 is a section similar to Fig. 3 of a modified form of the present accessdoor; and',

Fig. 5 is any elevation of afra'gmenta'ry' structureha'vingI anaccess opening 'constructed' in" accordance "with'this invention, showing the developmetof' the access' openiffd Stat?? 2,783,007 Patentedy Feb. 26,

ice

ing and the simultaneous creation of a stop to control and guide the movement of a door to be as sociatedtherewith in its removal from and replacement in the access open- While, as hereinabove set forth, this invention can be appliedl generally to all openings adaptedV to be closed by a removable door or closure, it has especial utility in aircraft Where the s kinof the components thereof, suchas wings, fuselages', etc'. is pierced by one or more access openings, veachmof ,which is to be closed by arem'ovable door and where the aerodynamic features and characteristics of the components must be retained.` YAccordingly, the present invention will be :described inconjunction with an aircraft component having an access opening therein to be closed by al door whichmay be readily and repeatedlyv mounted in land removed from this opening in the component.

In aircraft, particularly 0f the military type, suchas fighter and pursuit airplanes, internal space isvery limited and the intricate and complex Amechanisms and lequipment of `the aircraft are so compactly enclosedor housed Within the componentes thereof that `they often are not readily accessible for repair, adjustment, replacement or maintenance. Sometimes it is necessary to remove entirely several units,- mechanisms, wiring and the like in ordery to reach and service a single piece of equipment or apparatus. Such removal' is invariably a diicult and expensive procedure and often results in breaking or damaging the equipment.

To overcome the foregoing diiculty, it has become common 'practice to form openings in and through the outer structure or skin of the aircraft or component, each situated adjacent a particular mechanism or piece of equipment andthrough which access may b e had thereto. Since it is important that the outer surface of Aan aircraft be maintained smooth and aerodynamically clean, it has also become common practice to provide doors or closures for closing' the access openings.

In the past, many forms of access doors or closures have been devised, but each has had one or more undesirable and objectionable features. For example, one form of .previously known access doors utilizes a plurality of spring ngers that engage the periphery of the access opening'- tomaintain the door in position on the associatedstructure. Access doors of this type are some-y what similar in construction'to the commonly known caps used to close the radiator or fuel tanks of automobiles. Such constructions are objectionable in that upon removal to open theaccess opening, Athe door or closure is nov longer attached to the structure and may be easily misplaced or lost. Moreover, inthe event the tension of the spring tingersis reduced for some reason or other, the door becomes loose andV will either produce undesirable rattles or f all out ofthe access opening' Another form of previously known access doors, embodies a plurality of snap or spring fasteners, or bolts, that are carried by the door andwhich engage complementalttings mounted to the structure defining thev access open ing. Here, the objectionable features include the, necessity-of opening or removing a large number of fasteners or bolts before the doork can be removed;v In addition, upon removal the'door is detached from the aircraft and may be readily lost or misplaced. An attempted solutionto theY latter problem is to tie or-securethe door to its associatedv structure by a lengthof wire or chain, but it has been foundthat in rsuch instancesthe'door swings or rubs against the structure of the aircraftandscratches or mars the outer `surface thereof.

means for mounting the door to the aircraft structure is constructed and arranged to the end that the door is tirmly secured against displacement when in its closed position and `remains attached to `the structure when in` the` open position thereof. Moreover, the mounting means includes means whereby the rotation of a single member thereof serves to displace the door relative to the access opening to open and close the same.

Referring now to the drawing, and more particularly Figs. 1, 2 and 3 thereof, the reference character 10 designates a fragmentary portion of an aircraft component, such as a fuselage, wing, or nacelle having an access opening 11 formed therein in convenient association with apparatus or mechanism (not shown) disposed or mounted within the component. Access opening 11 may be of any desired size and shape, but it has been found that a generally circular opening is more satisfactory for most purposes.

A closure assembly 12 is operatively associated with the opening 11 and is positioned normally to close the same. Closure assembly 12 comprises a plate 13 which underlies the outer structure or skin of component 10 and which is operatively connected thereto through a bolt or screw 14 as will hereinafter be more fully set forth. Plate 13 may be of any desired configuration, but as shown in Fig. 1 is generally oval in shape, somewhat greater in area than the access opening 11 in cornponent 10 and relatively thin. Adjacent one of its ends, plate 13 is pierced by a hole 13 for the unrestricted passage therethrough of screw 14, while adjacent its opposite end, plate 13 is provided with a projection or door 15 which is immovably secured, as by welding for eX- ample, to the outer face thereof. Door 15 substantially conforms in shape and area to the access opening 11 and is of the same thickness as that of skin 10' of the cornponent 10. Thus, when the door 15 is seated or disposed in the access opening 11, it completely fills said access opening 11 with its outer face lying in the plane of the outer surface of skin 10 so as to create a smooth continuation thereof. The hole in skin 10' of the component 10 through which the screw 14 passes in countersunk, as at 16, to receive therein the head of said screw to thereby preserve the smooth or uninterrupted outer surface of the skin 10'. Moreover, countersunk hole 16 is slightly larger than the threaded shank of screw 14 `to provide a small clearance therebetween, thereby preventing the engagement of the threads with skin 10'.

Secured or immovably fixed to the underside of plate 13, in oppositionr to door 15, is a nut 17 having one or more ears or lugs 18, each having a central aperture thereinthat registers with an aperture formed in plate 13. Suitable fastening means such as pins or rivets 19 Apass through these registered apertures to secure nut 17 4the registered holes and threading it into nut 17. The

threaded portions of screw 14 and nut 17 are designed for a substantially tight-fitting engagement with each other to the end that the frictional load therebetween causes the `nut 17, and hence plate 13, to rotate with screw 14 about the` axis of rotation of the latter in the absence of a restraint placed upon either nut 17 or plate 13. Door 15 `is positioned on plate 13 relative to hole 13', and hence the axis of rotation of screw 14, and access opening 11 is positioned relative to countersunk hole 16 so that access opening 11 lies in the path of rotation of door 15. Thus, by rotating screw 14, door 15 can be rotated to a point where it is in axial alignment with access opening 11 and in registration therewith.

To provide means for preventing the rotation of plate 13 by screw 14 when door 15 is in axial alignment with access opening 11 and to cause a linear movement of plate 13 along screw 14 in alignment with access opening 11 upon continued rotation of the latter, a stop or guide member 20 is mounted or secured to skin 10 of component 10 in any suitable manner, as for example by a pin or rivet 21, so as to project inwardly thereof and lie in the path of rotation of plate 13. The position of stop 2G relative to the access opening 11 and plate 13 is such that when one edge of plate 13 engages the side of stop 20, as shown in Fig. 1, door 15 is located in vertical, axial alignment or registration with access opening 11.

Due to the foregoing construction and arrangement, when the parts are situated as shown in Figs. 1 and 2, and it is desired to open access opening 11 to obtain access to internal mechanism or equipment within the component 10, a suitable turning tool such as a screw driver is inserted in the slotted head of screw 14 and turned to rotate the latter in a counterclockwise direction as viewed in Fig. l. The frictional engagement between the coacting threads of screw 14 and nut 17 tends to rotate the latter and plate 13 in a counterclockwise direction, but such rotation is prevented by the engagement of door 15 with the periphery of opening 11. Therefore, plate 13 is moved linearly along screw 14, drawing door 15 out of access opening 11. When the outer surface of door 15 clears the inner edge of access opening 11, plate 13 is freed to rotate in a counterclockwise direction with screw 1 4 thereby moving door 15 out of registration with access opening 11 and permitting access therethrough. Once door 15 has been moved out of alignment with access opening 11, further rotation of screw 14 is unnecessary. However, in the event of further rotation of screw 14, plate 13 engages stop 20 to prevent the realignment of door 15 with access opening 11.

To reposition door 15 in access opening 11 to close the same, screw 14 is rotated in a clockwise direction, thereby rotating plate 13 until the edge thereof engages stop 20. At this time, door 15 is in axial alignment with access opening 11, and since stop 20 prevents further rotation of plate 13, the latter moves axially along screw 14 and door 15 is moved and guided into access opening 11 to close the same. The rotation of screw 14, after plate 13 has engaged stop 20 and `door 15 is seated in access opening 11, serves to securely hold door 15 in its closed position.

Thus, it may be said that stop 20 serves a multiple purpose, in that during the opening operation of screw 14 it prevents the possibility of the realignment of plate 13 and access opening 11; and during the closing operation of screw 14 it arrests the rotation of plate 13 with its door 15 in vertical alignment with opening 11 and serves to guide the former into position in the latter.

Similarly, screw 14 also serves a multiple purpose in that, during the opening and closing operations, it serves to move plate 13 both linearly and rotationally, while upon the completion of the opening or closing operation it serves, in the rst instance, to maintain door 1S attached to component 10 and, in the latter instance, firmly secures door 15 into the closed position thereof.

As above set forth, once closure or door 15 has been removed from access opening 11 in skin 10', continued rotation of screw 14 is unnecessary, since access may now be had within component 10.` Therefore, the provision of a relatively long shank on screw or bolt 14- alone will normally sutiice to prevent the separation of screw 14 and nut 17 to the'end that the closure assembly does not fall into the component 16 and become lost. However, where a positive retaining means is desired, this may be attained in many well-known and self-suggestive ways, one of which, by way of example, is the provision of a washer 22 retained on the shank of screw 14 by means of a transverse pin or cotter key 23 at or adjacent the cnd thereof.

arance? a screw or bolt 14n which serves to operatively connect' closure 12a to skin 10a of component 10. A countersunk hole 16a is provided in the skin 10a for the passage therethrough of the screw 14a.

Adjacent .the other end of closure 12a a projection or lug 15a is created by forcing one surface of closure 12a outwardly in opposition to the nut 17a at the other end thereof. The area of the outer face of the projection 15a is made to correspond in size and shape with an access opening 11a which has been formed in the skin 10a of the component 10. It is to be noted that the edge of the skin a, which defines the access opening 11a therein, is rounded or bevelled, particularly the inner or under edge thereof, to permit mating contact land cooperation with the outer surface of closure 12a which defines the projection a.

The relative position of the projection 15a of closure 12a with respect to nut 17a is such that when the closure is operatively connected to the Skin 10a of component 10 through the bolt 14a, as above described, access opening 11a in the skin will lie in the path of rotation of projection 15a around said bolt 14a.

In this form of the invention, a modified means for controlling the rotation of closure 12a during the opening and closing operations of bolt 14a is provided. More particularly, to insure the alignment of projection 15a with access opening 11a when bolt 14a is operated rto move the former to its closed position and `to prevent the realignment of projection 15a with access opening 11a when bolt 14a is operated to move projection 15a to its open position, a stop or guide a is provided which consists of a downward-turned tab of the skin 10a. The operation and function of stop 20a is identical in every respect to the guide 20 of Figs. l, 2 and 3, las hereinabove described.

Fig. 5 illustrates `the preferred manner in which stop 20a may be formed. A three-sided cut 24 is made in skin 10a laterally adjacent the place where access opening 11a is to be made in skin 10a of lcomponent 10. The portion of skin 10a defined within this three-sided cut 24 is then turned downward or inward, as at 26, to a position where it is substantially normal to the remainder of skin 10a and lies in the path of rotation of projection 15a about the bolt 14a during the closing and opening operations thereof. In making the threesided cut 24, it is necessary that the opposed sides :thereof extend from a point within the area 27 which is to be removed in forming the access opening 11a to a point beyond what is to be the limits of the removed area 27, a distance substantially equal to the thickness of the material which constitutes skin 10a plus the distance between the periphery of projection 15a and the edge of closure 12a. The reason for this requisite is to assure alignment of projection 15a with access opening 11a in the closing operation of bolt 14a whereby said projection is made to close the access opening in the skin 10a. Finally area 27 is cut out or removed thereby creating the access opening 11a in skin 10a.

From the foregoing it is seen that -the operation and function of both forms of the invention is identical, the only difference being in structure and technique of manufacture. The form selected or preferred in use will largely depend upon the particular application.

Moreover, it is to be understood that, if desired, the retaining means 22 and 23, as shown in Fig. 3, may be employed with equal effect and in the same manner in the form of the invention shown in Fig. 4 without departing from the scope of the invention. Conversely, as above pointed out, means 2.2 and 23 may be omitted from the form of lthe invention illustrated in Figs. 1, 2 and 3. Also either stop or guide, viz. stop 20 or stop 20a, may be employed in either form of the invention shown and described without departing within the scope hereof. Moreover, in the form of the invention shown in Figs. l, 2 and 3, nut .17 may be of the self-locking type in order to provide for the frictional load between screw 14 and nut 17.

What is claimed is:

1. The combination with an aircraft skin having a pair of openings therein, one being an access opening and the other a mounting and operating opening, of a closure for said access opening adapted to be `disposed in and withdrawn from said .access opening by movement thereof normal to the skin, a plate disposed adjacent the inner surface of the skin and normally extending across both of the skin openings, the closure aforesaid being secured to the portion of the plate in normal alignment with'the yaccess opening, a lobe having a threaded passage secured to the plate in alignment with the operating opening, a screw having a -liead normally engaging the skin and a shank threaded into the passage of the lobe, the rotation of the screw in one direction initially moving the plate away from the skin to withdraw the closure from the access opening and its continued 4rotation in that direction then swinging the plate to remove the closure from alignment with the access opening and the rotation of the screw in the opposite direction swinging the plate to -align the closure with the access opening and its continued rotation in that direction then moving the plate toward the skin to seat the closure in the access opening, and a stop secured .to the inner surface of the skin in the path of swinging movement of the plate both after the removal of the closure from the access opening and as the closure swings in the opposite direction to align with the access opening.

2. The combination with an aircraft component normally disposed in the airstream Vand having an access opening and a chamfered mounting and operating opening therein, `of an oblong plate substantially greater in length than the distance between the most remote edges of the skin openings and substantially wider than either opening, a nut secured to the plate adjacent one end thereof, a countersunk screw having a head and a shank extending through said operating opening, said shank being threaded `into the nut, said head being normally in engagement with said skin, a closure conforming in shape and area to the access opening and equal in thickness to the skin, secured to the plate and disposed in a path of rotation about the screw intersecting the access opening, and a xed stop carried by and projecting from the inner surface of the skin to arrest movement of the plate as it swings with the rotation of the screw to align the closure with the access opening and continued rotation of the screw thereafter disposes said closure in the access opening with its outer surface in the plane of the outer surface of the skin.

References Cited in the le of this patent UNITED STATES PATENTS 576,051 Gillespie Jan. 26, 1897 1,918,079 Arcier et al. July 11, 1933 2,159,477 vFriedman May 23, 1939 2,525,217 Glitsch Oct. 10, 1950 2,652,169 Brusienski Sept. 15, 1953 FOREIGN PATENTS 18,616 Great Britain 1913 72,245 Germany Dec. 1, 1893 478,365 Great Britain Jan. 18, 1938 683,008 Germany Oct. 27, 1939 

